A surface-mount type package with a quartz resonator mounted on a surface-mount base is compact and lightweight, and therefore is used often for a built-in purpose in, in particular, portable-type electronic equipment. Normally, in such a type of package, a quartz resonator is sealed after being mounted on a surface-mount base. For example, JP 2003-297453 A describes a surface-mount base with a consideration given to the compatibility with a circuit board on which the quartz resonator is to be mounted.
FIG. 9 is a cross-sectional view of a package of a quartz resonator using a surface-mount base that is described in JP 2003-297453 A. Although not illustrated, a planar configuration of the package is rectangular, and FIG. 9 shows a cross section along its longitudinal direction. Reference numeral 21 denotes the surface-mount base, including an insulative supporting member 22, a pair of metal lead terminals 23 and a sealing glass 24. On a top surface of the surface-mount base 21, a quartz resonator 25 is mounted, and a cover 26 is put over the quartz resonator 25.
The supporting member 22 is made of ceramic, for example, and has a pair of through holes 27 at both end portions of the quartz resonator. Each of the lead terminals 23 includes: an element connecting terminal 23a, a lead portion 23b and a mounting terminal 23c. The lead terminal 23 is mounted to the supporting member 22 by passing the lead portion 23b through the through hole 27. The through hole 27 is filled with the sealing glass 24 for sealing the lead terminal 23 in the through hole 27, whereby the airtightness of the surface-mount base 21 is obtained. The element connecting terminal 23a of the lead terminal 23 is placed so as to face the top face side of the supporting member 22 and is connected with an electrode of the quartz resonator 25 by a conductive adhesive or the like. The mounting terminal 23c is disposed so as to face the bottom face side of the supporting member 22 and is used as a terminal for the mounting to a circuit board. The element connecting terminal 23a and the mounting terminal 23c are bent horizontally in mutually opposite directions relative to the lead portion 23b extending in the vertical direction.
The through-hole 27 is filled with a solid glass as the sealing glass 24, which is then baked integrally with the supporting member 22 and the lead terminals 23. Thereby, the solid glass is fused to be integrated with the supporting member 22 and the lead terminals 23, so as to form the surface-mount base 21.
The cover 26 is made of an insulation material such as ceramic, and is bonded to the outer edge of the surface-mount base 21 by, for example, glass sealing.
In this package, the mounting terminal 23c of the lead terminal 23 is connected with a circuit terminal portion (not illustrated) of the circuit board with a solder by conveying the package through a high-temperature oven, for example. At this step, since the metal mounting terminal 23c has elasticity, this element absorbs a difference in expansion coefficient between the supporting member 22 made of ceramic and the circuit board (glass epoxy substrate or the like). Therefore, an external force applied to the connection portion between these elements can be alleviated by heat cycle and the like, thus avoiding cracks and chipping generated in the solder, for example.
During the procedure for manufacturing the thus configured surface-mount base 21, when the lead terminal 23 is attached to the supporting member 22, the lead terminal 23 is passed through the through hole 27 and then in the state of fixing the lead terminal 23 with a jig or the like, the solid glass is charged therein. However, in order to make it easy for the lead terminal 23 to pass through the through hole 27, it is necessary for the through hole 27 to have a sufficient size, and therefore the lead portion 23b of the lead terminal 23 rattles in the through hole 27, thus making the positioning unstable, so that it is difficult to handle during the manufacturing process.